Bing is actually taking this
initiative a step further by using the META keyword tag to penalize
websites which are abusing them. Abuse of the META keyword
tag has always been an issue, and it's to the point where the
information within that tag can no longer be used to help search
engines determine keyword relevance on a page. Going forward,
if Bing determines that a web page's META keywords do not apply
directly to the content within the website, Bing will penalize that
web page for "keyword stuffing".

So the next time you receive
advice from someone about adding META keywords to your site, ignore
them. As the following article discusses, you are better off
leaving META keywords completely blank rather than risking search
engine penalties: